My career goal is to establish an academic research laboratory devoted to understanding how pathogens affect the nervous system, and what features of neurons could provide useful therapeutic targets to combat these infections. I am well-prepared to contribute significantly to our understanding of neurotropic pathogens, based on the strong foundations of my graduate training in neurobiology and postdoctoral training in virology. This award will facilitate my career development by allowing me to gain training in bioinformatics and immunology, and also by providing funding and time to generate data and publications to facilitate a future R01 application. The overall goal of this research proposal is to understand how pathogens interact with the host nervous system, specifically to grasp what genetic features can make a neurotropic pathogen more or less virulent. Herpes simplex virus 1 (HSV-1) is a widespread human pathogen that establishes latency in human peripheral neurons and reactivates repeatedly throughout a patient's lifetime. HSV-1 is a leading cause of infectious blindness in the United States, and the main cause of sporadic, fatal encephalitis. It is unknown why certain HSV-1 infections progress to the level of encephalitis, but it is almost certainly influenced by both viral and host factors. Mouse models of this disease have demonstrated that viral strains differ in their virulence and ability to cause encephalitis. However the ability to map these phenotypic differences to specific viral genes has been limited by the lack of comparative genomic information about this virus - only one wild type HSV-1 genome has been known for the last two decades. I recently demonstrated that high-throughput sequencing (HTS) and bioinformatic assembly can be used to obtain further HSV-1 genomes. I propose to use HTS to test this hypothesis: that genetic loci which are enriched in neurovirulent strains, and lacking in strains that do not cause encephalitis in mice, are highly likely to be causally associated with the neurovirulence phenotype. To achieve this, my specific aims are: (1) to use HTS, genome assembly, & bioinformatic comparison of diverse clinical isolates of HSV-1, to find loci that are enriched in highly neurovirulent strains versus non-virulent ones; and (2) to generate viral recombinants, by either adding or removing putative neurovirulence loci, and test for associated changes in phenotype using an in vivo model of viral encephalitis. These aims will lead to future research directions, using standard molecular and cell biological approaches to explore how these neurovirulence loci affect neuronal function and the viral infectious cycle. This proposal will shed light on mechanisms of neurovirulence in this pervasive human virus, and highlight aspects of virulence to consider in other neurotropic pathogens. NARRATIVE: Herpes simplex virus 1 (HSV-1) is a widespread human virus. This research will investigate how HSV-1 virus isolated from one patient may differ from that of another. This will help us understand why some patients suffer more severe symptoms from HSV-1 infection than others.